1. Field of the Invention
The present invention relates to a device for applying adhesive tape to the winding core of a web processing machine in general, and photographic web processing apparatus in particular.
2. Description of the Prior Art
Photographic sheet materials are often manufactured in the form of a web which is wound onto a winding core. The winding core is usually positioned at the end of the coating or processing machine. As one core becomes full, it is necessary to replace it and insert an empty core onto which further processed web may be wound. Processing machines are operated at high speed for reasons of economy and it is desirable not to have to stop or slow down the processing while winding cores are changed. Such processing machines therefore may include devices for cutting the processed web, moving a full core out of position and moving an empty core into position automatically and at high speed. The cut end of the web has to be reliably adhered to the empty winding core and in the past this has been achieved by the application of adhesive to the winding core before it is moved into position. Such a process is described for example, in U.S. Pat. No. 4,422,586 (Tetro/The Black Clawson Company), where a strip of adhesive is applied along the length of a winding core for this purpose. Since the photographic sheet material is cut while the machine continues to run, by running of a cutting blade across the web of sheet material, an angled cut is produced. The fresh end of the web is therefore angled in a predetermined manner and it is important to ensure that the point of this angle is reliably adhered to the empty winding core. Thus, it is appropriate to apply a circumferential line of adhesive to the winding core at an appropriate position along its length. The strip of adhesive may be in the form of a length of double-sided adhesive tape, applied to the winding core. The double-sided tape is applied by an operator using a hand-held tape dispenser comprising first and second applicator rollers and a support for a supply of adhesive tape, the support being so positioned to allow a run of adhesive tape from the supply to the first applicator roller and thence to the second applicator roller, with an adhesive side facing outwardly.
In applying the tape to the core, certain conditions have to be satisfied. The leading edge of the adhesive tape has to be applied to the winding core by hand. The winding core must rotate by at least one revolution to obtain a complete encirclement of the winding core by the tape. The tape must be positioned at exactly the correct position along the length of the core. All these conditions are difficult to ensure under low-light conditions or in darkness.